Hey, Well I have 91 4Runner that I've had for a week now with the wonderful ADD! It wasn't working and I confirmed this by jacking up the back tires in 4wd and nothing happened with the front to make it move. So I checked the vacume lines going to the ADD and there is very little if anything going to them. Checked the vacuum lines before the solenoids nothing much more.

So I went ahead and switched the vacume lines going to the ADD around so the one that was hodling it open is now holding it close and it works! So what could that mean? Relay, solenoid, fuse?

 

http://www.off-road.com/trucks4x4/ar....jsp?id=399612

See if that article sheds light on anything.

 

could just swap em out for some manual aisin hubs, if thats to your liking

 

Yeah I read that article, but I can't find my relay. I probably will end up switching to the Locking hubs, but right now I want to fix the relay so that my 4wd light comes on. I got it to engage and work but my 4wd light will come on.

Does anyone know where the relay is? I looked on the passengers side of the steering column and only found the fuel pump relay.

 

Well I ended up just keeping them switched and took it four wheeling. I think it just needs a add relay but this was my first time 4 wheeling in a toyota and let me tell you it was awesome!!!

It made it through deep mud no problem and we went up some pretty steep hills at the Lake. I through my dogs in the back and they loved it too.

Only thing that wasn't right was the passenger side idler arm. It needs rebuilt. It was really loose and about to fall off. Glad we made it home

 

Buy a brace for the idler (if you can find a used one, or make one) Those things are super common to wear out if you wheel yer rig.

If the bushings are just bad, the dealer sells replacements for $10 or so..

 

Or upgrade to the brass bushing kit from SDORI. I'll be doing that when my idler arm wears out.